Cutting tool



Patented Aug. 27, 1940 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to a cutting tool consisting of a metal punch anddie.

One object of my invention is to provide a tool to punch holes in sheetmetal by hand which is simpler to use and more certain in attainingdesired results than those heretofore known. I am aware that punches anddies to make holes in sheet metal by hand are well known; but they arein several respects unsatisfactory, and it has been my principal objectto substantially improve them by having only-two separate parts, andsoconstructing these parts that they interfit and operate in such amanner that the desired holes will correctly be cut out, even though theinitial positioning of the punch and die together is not done accuratelyor the hammering done unevenly.

Another object is to provide such a tool that will shrink or lessen thewidth of the piece it cuts out so that it will not bind when it is beingremoved. Still another object is to accomplish the foregoing and otherobjects with a tool of such construction that is economical and simpleto manufacture, and practically certain to attain the desired resultseven when faultily used.

The foregoing and other objects which will appear as the nature of theinvention is better understood, may be accomplished by a construction,combination and arrangement of parts such as is disclosed by the drawingand specification. The nature of the invention is such as to render itsusceptible to various changes and modifica tions, and, therefore, I amnot to be limited'to said disclosures; but am entitled to all suchchanges therefrom as fall within the scope of my claims.

In the drawing:

Figure 1 is a front elevational view of my punch and die separated.

Figure 2 is a plan view of my die.

Figure 3 is a plan view, broken away, showing a piece of metal betweenmy punch and die, ready to have a hole cut in it.

Figure 4 is a front elevational view, partly in section, showing a pieceof metal resting on top of the die with the punch directly overheadready to be placed in position with respect to said die to cut a hole insaid piece of metal.

Figure 5 is a sectional view, broken away, showing the punch and die anda piece of metal with a piece cut out of it, leaving a hole, at thecompletion of the cutting operation.

My punch P consists of a main body portion Ill preferably having a fiatlevel bottom surface extending from the outer edge inwardly a shortdistance. A pilot or centering pin II is fixed in said body portion land projects beyond the end a short distance, terminating in a taperedportion l2. A recess I3 is formed in the lower portion of said body l0,extending inwardly and upwardly into the interior and being preferablyof greater depth than the die recess l6 later described.

My die consists of a main body I4 at the top of which is formed a topface outer rim l5,'having inner and outer sides which extend straightdownwardly therefrom. Extending inwardly 10 from the inner edge of saidtop face outer rim I5 is a bore or recess l6, adapted to receive thecutting or end portion of said punch P, the bottom of which recessslants downwardly towards the outside as at H, terminating at itsoutside and is lowest point, as shown in Figures 4 and 5 of the drawing.Surrounding a hole formed in said body M at the center thereof is a bossor raised portion l8 which preferably'is substantially level with saidtop face outer rim l5. Said pilot pin 20 ll fits into said hole 20 andthereby assists in accurately positioning the punch P in said die D.Said boss or raised portion l8' makes it possible to use a short pilotpin I l which need extend beyond the body of said punch P only a shortdistance, this extending portion being the tapered part l2 which isthereby enabled to more easily enter said hole 20 should it bemistakenly positioned a little off to one side of said hole 20. Becausethis extending part of the said pilot pin II is so short and tapered itis unlikely to be broken or bent should the punch P be struck unevenlyor not enter the recess IS in said die in the position it should duringthe cutting operation.

As will be noted in Figure 5 of the drawing said boss l8 extends intosaid punch recess l3 during the cutting operation which forms the hole2|, and part of the severed part 22 of the metal sheet M also extendstherein because it bends upwardly, which shrinks it in width. As shownin Figure 3 of the drawing, before the punching operation is begun, itis desirable to drill or otherwise make a small hole 23 in the piece ofmetal M through which said pilot pin ll may extend and enter said diehole 20.

My tool is used by laying a piece of metal M over the top of said die Dwith the hole-23, that is previously made in said piece of metal M,directly over the hole 20 in said die D, and inserting the said pilotpin l I through said hole 23 and into said die hole 20. Hammering onsaid punch P cuts out a hole 2|, the middle portion of the out part 22being bent so that it slants upwardly towards the center thereof,thereby shrinking its 5 diameter so that it will be slightly smallerthan said hole 2| and not bind when being removed back through the holepunched.

By forming said die recess l6 so that its lowest point is outermost, theoutside or shearing edge of said punch P will not touch said die at thispoint, as illustrated in Figure of the drawing, thereby avoiding anylikelihood of damaging my tool or locking said punch and severed pieceof metal 22 in the said recess 16.

What I claim is:

l. A cutting tool comprising a punch having a recess and having a flatbottom surface of narrow extent adlacent the outer edge of said punchand outside of said recess, and having a pilot pin extending beyond theend thereof, and a die having a hole therein adapted to receive saidpilot pin end, and having a recess outside of said hole into which aportion of said punch may enter during the cutting operation, said diehaving a boss portion outside of said hole, said recess commencing atthe termination of said boss portion and slanting downwardly andoutwardly evenly to its outermost point.

2. A cutting tool comprising a punch having a flat bottom surfacecommencing at and extending inwardly from the outside edge and having apilot pin extending beyond the end of said punch, and a die having ahole therein adapted to receive said pilot pin end, and having a recessoutside of said hole into which a portion of said punch may enter duringthe cutting operation, said die having a boss portion outside of saidhole, said'recess commencing outside of said boss portion and extendingdiagonally downwardly and outwardly.

3. A cutting tool comprising a punch having a pilot pin extending beyondthe end thereof and having a recess therein extending inwardly from saidend, a die having a hole therein adapted to receive said pilot pin end,and having a boss portion outside of said hole and a recess outside ofsaid boss portion into which a portion of said punch may enter duringthe cutting operation, the maximum depth of said punch recess beinggreater than the maximum depth of said die recess.

4. A cutting tool comprising a punch having a pilot pin embodying astraight shank portion and a reduced end portion extending beyond theend thereof and having a recess therein extending inwardly from saidend, the distance said straight shank. portion extends beyond said endbeing less than the length of said reduced end portion, and a die havinga hole therein adapted to receive said pilot pin end, and having a bossportion outside of said hole and a recess outside of said boss portioninto which a portion of said punch may enter during the cuttingoperation, the distance said pilot pin straight outside of said bossportion into which a portion.

of said punch may enter during the cutting operation, the outside end ofsaid pilot pin being tapered, said tapered portion commencingsubstantially opposite the deepest point of said die recess when saidpunch is in cutting position in said die.

6. A cutting tool comprising a punch and a die, said punch; having aflat, bottom surface extending inwardly from its outside edge and arecess extending from the inner edge of said surface interiorly into thebody of said punch, a pilot pin fixed in the body of said punch having atapering outer end which extends beyond said surface outwardly, said diehaving a hole therein adapted to receive said pilot pin, a boss portionadjacent to and surrounding said hole, a recess extending from andaround said boss portion into the interior of said die adapted toreceive the whole end portion of said punch during the cuttingoperation, the bottom of said recess slanting downwardly and outwardlyin the same angular direction continuously to its terminating point, anda top face outer rim extending inwardly from the outside edge of saiddie the top surface of which is in a horizontal plane and substantiallyeven with the top surface of said boss portion.

'7. A cutting tool comprising a punch and 9. 40

die, said punch having a flat, bottom surface extending inwardly fromits outside edge and a recess extending from the inner edge of saidsurface interiorly into the .body of said punch, a pilot pin mounted insaid punch having a straight shank portion that extends beyond the endof said punch a distance less than twice the maximum depth of said punchrecess and havin a tapering outer end which extends beyond said shankportion, said die having a hole therein adapted to receive said pilotpin, a boss portion adjacent to and surrounding said hole, a recessextending from and around said boss portion into the interior of saiddie adapted to receive the whole end portion of said punch during thecutting operation, and a top face outer rim extending inwardly from theoutside edge of said die having a top surface substantially level withthe top surface of said boss portion.

FRED F. RULAND.

